美托洛尔对急性心肌梗死患者QT离散度及心率变异性的影响

目的研究β-受体阻滞剂时急性心肌梗死（Acute myocardial infartion，AMI）患者QT离散度（QT dispersion，QTd）及心率变异性（Heart rate variability，HRV）的影响。方法将45例急性心肌梗死患者随机分为两组：试验组（24例）和时照组（21例）。时照组接受常规治疗，实验组在常规治疗的基础上加用美托洛尔治疗．测定两组患者入院后第一天及四周后的12导联心电图，三周后的24小时动态心电图，比较两组患者治疗前后的QTd、心率校正QT离散度（QTcd）、最大QT间期（QTmax）、最小QT间期（QTmin）及HRV的各项时域指标。结果与时照组比较，试验组四周后的QTd、QTcd显著减少，QTmin明显延长，QTmax保持不变，三周后HRV的各项时域指标与对照组相比均不同。结论急性心肌梗死患者早期使用β-受体阻断剂（美托洛尔）能缩小心肌复极化的离散程度，使心肌复极趋向同步，并可提升HRV，改善失衡的自主神经。

Effect of Metoproloi on QT dispersion and heart rate variability in patients with acute myocardial infarction

Objective To evaluate the effect of β-blockers on QT dispersion and heart rate variability in patients with acute myocardial infarction. Methods 47 patients with acute myocardial infarction were divided into trial group （24 cases） and control group （21 cases） by random. The control group was treated by conventional therapies without β- blockers, and the trial group by conventional therapies and Metoprolol. The 12-lead electrocardiogram （ECG）of two groups was obtained on the first day of hospitalization and 4 weeks later, and 24-hour dynamic electrocardiogram was conducted to monitor the heart rate variability （HRV） after three-week treatment. QTd, QTcd, Qtmax, Qtmin, and the time domain values of HRV were compared between the two groups. Results Compared with control group, four weeks later, the QTd and QTcd in the trial group were significantly shortened （P〈0. 01） ,the QTmin significantly prolonged （P〈0. 01）, and QTmax did not change （P〉0.05）. Three weeks later, the time domain values of HRV were significantly different （P〈 0. 01 or P 〈 0. 05）. Conclusion Metoprolol can diminish dispersion of repolarization of ventricular myocardium by prolonging Qtmin, elevate HRV and improve imbalance of the autonomic nervous system at the early stage after acute myocardial infarction.